Industry Expert Chris Taylor-Hamlin, Technical Director
27/09/2010 | Question 1 Why does the push button valve leak on the new WC cistern I just installed? The cistern came factory fitted, in its own box, so I expected it to be perfect but it constantly dribbles into the pan. Factory fitted cisterns with push button dual flush valves are now very common. They are usually fitted and tested in clean conditions in the factory and reputable manufacturers do guarantee them against faulty workmanship and materials. In your case it sounds as though debris is lodged between the rubber flat-ring seal on the bottom of the moving part of the valve and the fixed valve seat. It is highly likely that in your new installation sticky particles of dirt have found their way into the cistern through the supply pipework and have somehow become trapped on the seal, creating the leak. This can be quite common in new installations and it is always advisable to flush out the pipework before commissioning. You need to clean the valve. This is usually a fairly simple procedure. Turn off the water to the cistern and remove its lid. Now remove the valve body – most twist to unlock them. Thoroughly clean the rubber flat ring seal and the seat. It may also be advisable to look for damage to the seal and seat. Now replace the whole valve and turn the water back on. Hopefully this will have cured the problem. If the leak persists you need to start looking for bad joints. Try between the pan and the cistern. Or the actual fixing of the valve to the cistern. ________________________________________ Question 2 My customer has called me to rectify very poor flow rates in his newly installed replacement bathroom (not sure who originally installed it). Both the washbasin and the bath filler taps have very poor flow rates and take an age to fill either. You don't mention the type of tap or the type of domestic plumbing system involved. But my initial thoughts are that the tap design does not match the plumbing system in the house. If the bathroom was installed by an amateur my guess is that he or she was not careful enough to ensure that the taps being installed were matched to the water pressure available in the property. Modern lever-action mixer taps require high water pressures for them to work adequately. An older property with a tank in the loft will have a low water pressure system. The manufacturers instructions should indicate the water pressure required by the taps for them to work adequately. My guess is that your customer's property is the older style with a low pressure system but the new taps require high pressure. So the two are mismatched. There are two possible actions – both expensive I am afraid. Either the taps have to be replaced by the more conventional low pressure type - they are available but tend to be more traditional in design. Or the pressure in property's water system needs to be increased by the installation of a pump. I would go for a simple pump but you need to do your homework to ensure that the correct specification is chosen and installation is made exactly to the manufacturer's instructions. ________________________________________ Question 3 My customer wants to become an eco-warrior and save water. He wants me to install a new WC which flushes using grey water from the bath and rainwater from a tub outside. This is all new to me and I'm a bit worried about it. Can you point me in the right direction? Our government wants to encourage the use of stored greywater and harvested rainwater for flushing toilets and watering the garden. It wants us to become more water efficient because some areas of the country are under increasing 'water stress'. The latest Building Regulations ( Approved Document G ) have been amended specifically to encourage water efficiency and have allowed, for the first time, the use of greywater in houses. Several greywater and rainwater harvesting systems are now available and they are growing in popularity. All systems require that the domestic plumbing system (ie the drinking water system) is kept entirely separate from the greywater system. The Building Regulations gives details of the careful and bold pipework labelling which is required. The last thing we want is the householder drinking his own bathwater. Your first step is to contact possible suppliers of greywater and rainwater harvesting systems. Speak to good reliable manufacturers with known brands to give you their advice about the products they produce for the exact situation you are hoping to convert. As an alternative, your customer may wish to consider one of the new combined washbasin and WCs. These self-contained single units store used water from the washbasin, filter and disinfect it, then use it to flush the toilet.